Electrically-heated hollow body.



No. 822,270. PATENTED JUNE 5, 1906.

E. HAAQN. ELBCTRIGALLY HEATED HULLOW BODY.

APPLICATION FILED JULY 7,1905.

' foils.

peceationof Letters atent,

Firm-1l AJA.

ernten. f

rneiliAU-ON-THE-MAN, GERMANY, ASSIGNOR TO THE o. HEi-IU GF FRANK?OR'lOiQ-THE-D/iAlN, GERiNL/filSlY.

.iLife-einigten Honneur, eem'.

recente@ June 5', 1906.

pplication filed Tilly 7, 1905. Serial No, 268,7'7.

e vin my poseoM n ,v' l f1 lie-main, Uerrneny,

llave invented 'certain row and use f1nl improvements iadectric- .ion/ing is a speciiicetion. ElectricaliyM nested 'li'ollovv bodies of ,conducting material have been known, which eiectical conductors are spiraiiy wound around tneliellow een 1e `ILL^ laitier als lldellCCl Dy bm:

ductors. Snc-ii Wires-or nieta-inc in tne German patent No. 42,152 an in- 1 l vention Wasi-disclosed accord--ng to which` the platinum-foil conductors are wound in rcffuiar spirals around end direct 'on cylindrical hollow bodies "(silcli as tubes of portae-y lain) Without using any embedding. 'In such? electricellydieated hollow bodies the platito be particularly bodies-suc`n as, for example, inutiles, cruci bles, and the like-notvevelg no platinum-foil conductors could be at all used, but vonly Wire coiis, which are mechanically secured on tile. hoilow bodies either oy means of special' eins, and the' means,

such as spiral grooves, nire or thereby a considerable saving in price. In

sucii ceses, 1now-ever, the Winding operation 1s most vdnciieult and, moreover, tile risk 1s incurred that the sever ai thin Wires might burn tlnfougli under nigh load byreason'- of slight detects, lwhich are .ur-.avoidable during tne l manufacture of the Wire orfinay arise during the Working of tne ile-ated hollow/bodies. My invention relates to an impiovernent'l'n suoli electricailylieated hollow bodiespvher'e- 'by eii'tliedeiects mentioned aboveam avoided and the life oi thespirel conductors. is.

- lengthened, l The said improvement consists bodiesso thatthe I lieat produced by the currents which pass through the con@ snirai c 'n'ductors Were eithery foils, particniarly platirnirn` with the aid oi a paste of reproof' ciay and the like.

high-current strengths, which,

in the L in Wliichl Fgure l isa perspective View of a retort or Inu'- e embodying the'A invention. Fig. 2 isa perspective vievt7 showin the strips of nete ting in e different forrn o Winding 'from that, illustrated in Fig. i, theloody of 'the inuie being omitted from' this view for purposes oiw clearness. s

'Referring to the drawings, A designates the body ci the Inutile or other liolloT body which is to be heated, and B designates a strip of Wire-netting Which is Woundv about said bedy A' and. is connected at its ends with the terminals of abattery-CI The netting strip or band may consist of a single' piece Wound in the niann'er' illustrated in Fig,

l, or a pluraiity of strips B', as shown in Fig.'

2, may be employed,l Inthe form of the invention'shown in Fig.- Z'the several strips are electrically connected bysiitable conductors ll-andttvo of the strips are connected with a' battery@ n'both forms of the invention it 1- Wili -be'seen that the conductor-material eX- tends in "spiral form about the body to be heated. v

lThe wire-nettin'gniay be produced on Wire 'looms *and consists'of liongitudinal 'Wires (gverps) and of cross-Wires,`(wefts,) 1n Winch' case the meshes are mostly square, or the Wire-netting may be produced on Wire-'netting niecliines of any known construction, in which case the rneshes inayeach 'have a po lygonel or square or rectangular or. parallelosections may Ieither-sin1ply engage in the neighboring meshes or' theyniay be twisted once or several'times, vras the case Vniay be.

The urne-netting 1s preferablyni'ade 1n strips, roo in which the several wires' 1n the vongitudinal direction are continuous, although they inay be bent invarious manners, according to the 'kind of the Wire-nettin; 'The strips of the i Wire-netting are applied to or upon the hol- -105 low "bodies (Inuflies, crucibles, and the like) 95 grammi/c or, any 'other shape, and the Wire and fastened or cemented thereon with a coating of melting or sintering mass, such as [ircproof clay or thel like.

The electrically-heated hollow bodies (inutiles, crucibles, and the like) provided with the strips of wire-netting as conductors for the heating electrical current present special advantages, as will be clear from the following explanations.

ln F ig. l a strip of wire-netting is shown as wound spirally around the hollow body, while in Fig. 2 the strips are not applied in a true spiral, but are laid side by side and electrically connected, so as to have the general effect of the s]')irally-wound strip when they are attached to the body in the manner above described.

When assumingl a hea-ting hollow body to be spirally wound with wires in multiple, as explained abovethat is to say, when several parallel wires are spirally wound around the hollow body and the area of either wire is contracted on a certain place from any reason, be it in the course of the manufacture of the wire or during the working of the heated hollow bod y-then the total electrical resistance of this single wire will not be essentially altered, so that the same' current passes through it as through the unhurt wires. For the short lengtl'i of the wire, however, where thc area contracted, a relatively considerable alteration oi" thc resistance will take place, and as this partof the wire is compelled to conduct the same current as any unhurt wire a great increase of the temperature will follow, which will contribute to the vaporization and destruction of the Wire on that place.

When employing strips of wire-netting in place of the parallel wires, however, the matter will be quite different. The wire-netting may be assumed to be woven on a loom, or, in other words, to comprise straight longitudinal wires (warps) and straight cross-wires (wefts) and to have square meshes, then practically the longitudinal wires alone will serve as conductors for the electrical current, while the cross-wires serve for regulating the tension of the current in the several longitudinal wires. Should either longitudinal wire have on-some place a reduced area or should this reduction in area be produced in the course of the time, then the respective part of this longitudinal wire will not need conduct the whole current passingthrouglrthis wire, but the excess of the current will be distributed over the remaining longitudinal wires by means ofthe cross-wires. In this manner the weakened part of the longitudinal wire Vbetween the respective two cross-wires need onl conduct a currentof less strength.. The Jou es heat JZWproduccd on the weakened place will be then sm aller than hitherto, seeing thatthe reduction of J is in proportion to the increase of W and that J is raised to a square. The consequence of the above facts will be that the conductors made of wire-netting will lastI much longer than those made of parallel wires, since each weakened part oi' the wire-netting will. be localized and preserved.

A further advantage of the wire-netting is i y the greater uniformity in the distribution of vthe heating-pipes of a greater cross-section has the tendency of detaching itself from the hollow body to be heated, so that not only heavy losses of energy will arise, but also the not-adhering parts of the foil will be so strongly heated as to waste in the run of the time.

Obviously the strips ,of wire-netting of other construction will present substantially the same advantages as described above.

What- I claim as my invention, and desire to secure by Letters Patent, i`s

l. The combinationwith a hollow body (muifle, Crucible, tube vand the'like) of nonconducting material, of a conductor consisting of a strip of wire-netting whichis applied upon said hollow body and cemented thereon, and means for passing a heating electrical current through said conductor.

2. The combination with a hollow body (Inutile, crucible, tube and the like) of nonconducting material, of a conductor consist-I ing of a strip of wire-netting which is applied -upon said hollow body and cemented thereon with a coating of melting mass, and means for passing a heating electrical current through said conductor.

3. The combination witha hollow body (muifle, Crucible, tube and the like) of nonconducting material, of a conductor consisting of a strip of wire-netting which is applied upon said hollow body and cemented thereon with a coating of sintering mass, and means for passing a heating electrical current through said conductor.

4. The combination with a hollow body (muilie, Crucible, tube and the like) of nonconducting material, of a strip of wire-netting comprising conducting-wires in the longitudinal direction and regulating-wires iny the transverse direction, this strip of wirenetting being spirally wound around said hollow body and cemented thereon, and means for passing a heating electrical current` through the conducting-wires in said strip of conducting material, of astrip of wire-netting comprising conducting-wires inthe longitudinal direction and regulatingiwires in the transverse direction, this strip of Wirenetting being spirally wound around said hollow body and cemented thereon with a coating of melting mass, and means for' passing a A heating electrical current through the conducting-wires in said strip of wire-nettmg.

6. The combination with a hollow body (munie, Crucible, tube and the like) of nonconducting material, of a strip of wire-netting compri sing conducting-wires in the longitudinal direction and regulating-wires in the transverse direction, this strip of wire-nettin being spirally wound around said hollow bo y and cemented thereon with a coating of sintering mass, and means for passing a heating electrical current through the conducting-wires in said strip of wire-netting.

In testimony whereof I have signed my name to this specification in th presence of two subscribing witness-N ERNST HAAGN.

W itnesses:

FRANZ H fissinicnnn7 ERWIN DIPPEL. 

